yoozef
10-19-2011, 08:10 PM
Over the summer I put a new s14 sr20 long block in my 240. The engine started and sounded good. But it would break up past 2k rpms. I tried to set the timing on it and followed the procedure. I unplugged the TPS, went inside the car to rev the car to 3k rpms, but around 2300 rpms it started knocking. I saw the check engine light come on and immediately shut the car off. FML.
I then tried to start the car and it started and ran (still knocking). I changed the rod bearings first, because I should’ve done it before so I just went for it. Started the car up, still knocking. So I pulled the head today and the valves show no sign of apparent damage. The tops of the pistons have some detonation damage.
#1
http://i29.photobucket.com/albums/c276/dzerek/1.jpg
#2
http://i29.photobucket.com/albums/c276/dzerek/2.jpg
#3
http://i29.photobucket.com/albums/c276/dzerek/3.jpg
#4
http://i29.photobucket.com/albums/c276/dzerek/4.jpg
I ran the engine for a total of maybe 15-20 minutes before it started knocking, so i'm pretty sure the damage is from previous owner? My question is, what would cause the car to immediately start knocking after unplugging the tps and going to 2k rpms other than bearings/bent valves? i'm stumped, the gas in the car is old mixed with 2 gallons of fresh 93 (my gas gauge doesn't work, so don't know how much old gas), but how would that cause an audible knock appear and stay after an attempt at setting timing? Chime in if you have any idea
My previous longblock had forged pistons in it and after a 1000 miles it had a lot of gunk on top of the JE pistons. Not sure if that’s related.
I then tried to start the car and it started and ran (still knocking). I changed the rod bearings first, because I should’ve done it before so I just went for it. Started the car up, still knocking. So I pulled the head today and the valves show no sign of apparent damage. The tops of the pistons have some detonation damage.
#1
http://i29.photobucket.com/albums/c276/dzerek/1.jpg
#2
http://i29.photobucket.com/albums/c276/dzerek/2.jpg
#3
http://i29.photobucket.com/albums/c276/dzerek/3.jpg
#4
http://i29.photobucket.com/albums/c276/dzerek/4.jpg
I ran the engine for a total of maybe 15-20 minutes before it started knocking, so i'm pretty sure the damage is from previous owner? My question is, what would cause the car to immediately start knocking after unplugging the tps and going to 2k rpms other than bearings/bent valves? i'm stumped, the gas in the car is old mixed with 2 gallons of fresh 93 (my gas gauge doesn't work, so don't know how much old gas), but how would that cause an audible knock appear and stay after an attempt at setting timing? Chime in if you have any idea
My previous longblock had forged pistons in it and after a 1000 miles it had a lot of gunk on top of the JE pistons. Not sure if that’s related.